//演示程序:邻接矩阵表示的带权有向图（网）
import java.io.*;
    //最大边数和顶点数
// “邻接矩阵”类
class Graph {    
    static int MaxEdges = 50;    
    static int MaxVertices = 10;
    static double MaxValue=9999.9;  //无穷大    
    //存放顶点的数组
    private char VerticesList[]=new char[MaxVertices];
    //邻接矩阵（存放两个顶点权值）
    private double Edge[][]=new double[MaxVertices][MaxVertices];
    private int CurrentEdges; //现有边数
    private int CurrentVertices; //现有顶点数
    //构造函数：建立空的邻接矩阵
    public Graph ( ){
        for ( int i = 0; i < MaxVertices; i++ )    
            for ( int j = 0; j < MaxVertices; j++ ) 
                if(i==j)
                    Edge[i][j] = 0; //对角线
                else    //非对角线上无穷大
                    Edge[i][j] =MaxValue; 
        CurrentEdges = 0;  //现有边数
        CurrentVertices = 0;  //现有顶点数
    }
    //查找指定的顶点的序号
    public int FindVertex (char vertex){
        //在顶点数组里面查找
        for(int i=0;i<CurrentVertices;i++)
            if(VerticesList[i]==vertex) 
                return i; //返回下标
        return -1;  //没有找到
    }
    //图空否？
    public boolean IsGraphEmpty ( ){ 
        return CurrentVertices==0; 
    }
    //图满否？
    public boolean IsGraphFull ( ){ 
        return CurrentVertices==MaxVertices ||
            CurrentEdges==MaxEdges; 
    }
    //取得顶点数
    public int NumberOfVertices ( ){ 
        return CurrentVertices; 
    }
    //取得边数
    public int NumberOfEdges ( ){ 
        return CurrentEdges; 
    }
    //按序号取得顶点值
    public char GetValue ( int i ){
         return i >= 0 && i <= CurrentVertices-1 
                  ? VerticesList[i] : ' '; 
      }  
    //取得一条边的权值
    public double GetWeight ( int v1,  int v2 ){
        if (v1 < 0 || v1 > CurrentVertices - 1) 
            return -1.0; //用-1表示出错
        if (v2 < 0 || v2 > CurrentVertices - 1) 
            return -1.0;
        return Edge[v1][v2];    
    }
    //取得第一个邻接点的序号
    public int GetFirstNeighbor ( int v ){
        if (v< 0 || v > CurrentVertices - 1) 
               return -1;  //用-1表示出错
    //邻接矩阵的行号和列号是两个邻接点的序号
        for ( int col = 0; col < CurrentVertices; col++ )
            if ( Edge[v][col] > 0 &&  //自身
                Edge[v][col] < MaxValue ) //无穷大
                return col;
        return -1; //无邻接点
    }
    //插入一个顶点
    public int InsertVertex ( char vertex ){
        if(IsGraphFull()) return -1;  //插入失败
        //顶点表增加一个元素
        VerticesList[CurrentVertices]=vertex;
        //邻接矩阵增加一行一列
        for ( int j = 0;j <=CurrentVertices;j++ ) {        
            Edge[CurrentEdges][j]=MaxValue;
            Edge[j][CurrentEdges]=MaxValue;
        }
        Edge[CurrentEdges][CurrentEdges]=0;
        CurrentVertices++;
        return CurrentVertices;  //插入位置
    }
    //插入一个边
    public boolean InsertEdge( int v1,  int v2, double weight){
        if (v1 < 0 || v1 > CurrentVertices - 1) 
            return false; //出错
        if (v2 < 0 || v2 > CurrentVertices - 1) 
            return false;
        Edge[v1][v2]=weight; //网,有向边
        return true;
    }
    //删除一个顶点
    public boolean RemoveVertex ( int v ){
        if (v< 0 || v > CurrentVertices - 1) 
               return false;  //出错
        //修改顶点表
        for(int i=v+1;i< CurrentVertices;i++)
            VerticesList[i-1]=VerticesList[i];
        //修改邻接矩阵
        int k=0;  //累计将要删去的边数
        for(int i=0;i< CurrentVertices;i++)
            if ( Edge[v][i] > 0 &&  //自身
                Edge[v][i] < MaxValue ) //无穷大
                k++;  //第v行
        for(int i=0;i< CurrentVertices;i++)
            if ( Edge[i][v] > 0 &&am